It is known that chocolate is made from cacao mass, cacao butter, sugar, powdered milk and the like. Cacao butter is mainly composed of POSt, StOSt and POP glycerides wherein P is palmitic acid, O is oleic acid and St is stearic acid. Typical chocolate which is eaten as it is as sweets (hereinafter referred to as "per se chocolate sweets") contain about 32% by weight of cacao butter. The P/St ratio as an average value calculated from total constituent fatty acids of the glycerides of the cacao butter is about 0.7 to 0.8. Other fats (hard butter) are often used as substitutes for all or a part of cacao butter in order to save production cost or to improve physical properties of chocolate.
In addition to use of chocolate as solid per se chocolate sweets such as bar chocolate, tablet chocolate and the like for tasting its own flavors, tastes and physical mouthfeel, chocolate is used as raw materials of confectionery in combination with other foods, more particularly, chocolate is used as, for example, coating materials, enrobers, filling materials and decorations of iced and baked confectionery. In general, excellent flavor, taste and physical mouthfeel are severely required in the case of the former use, i.e. in the case that chocolate is used as solid per se chocolate sweets.
The above-described hard butter which is used as a cacao butter substitute is generally classified into tempering and non-tempering types.
Hard butter of a tempering type is obtained from shea butter, sal fat, illipe butter, palm oil, a fractionated oil thereof or the like. Like cacao butter, the main triglyceride composition of hard butter of this type is composed of 2-unsaturated-1,3-disaturated triglycerides (SUS). The main constituent saturated fatty acids thereof are palmitic acid (P) and stearic acid (St). Recently, as a technique for obtaining hard butter rich in SUS, enzymatic interesterification has also been pervading. Because the hard butter of this type is very similar to cacao butter structurally, it is free from problems such as blooming and lowering of heat stability caused by using it in combination with cacao butter. However, when such hard butter is used in the production of per se chocolate sweets, tempering treatment is required.
Palm medium melting point fraction is hard butter of this type and is rich in POP triglyceride. Although palm medium melting point fraction is effective for improving melting properties of chocolate using cacao butter in the mouth, the amount thereof is very small (JP-A 53-115863) because the fraction is not suitable for per se chocolate sweets, while a relatively larger amount thereof can be used for raw materials for confectionery such as a coating material, an enrober, a filling material (for example, JP-A 60-221035). In addition, there is a problem that to mix palm medium melting point fraction with triglycerides other than SUS is remarkably limited even when it is used for per se chocolate sweets (for example JP-A 61-209545).
On the other hand, typical hard butter of non-tempering type is a trans-acid type or a lauric acid type. Hard butter of a trans-acid type is obtained by isomerization and hydrogenation of a fractionated soft part of palm oil or the like, or a liquid fat such as soybean oil. Hard butter of a trans-acid type is composed of triglycerides containing relatively larger amount of trans-acids in the constituent fatty acids. On the contrary, hard butter of a lauric acid type is obtained from a fat containing a large amount of lauric acid moiety such as coconut oil, palm kernel oil, babassu oil or a fractionated oil thereof and is composed of triglycerides containing a large amount of lauric acid in the constituent fatty acids. Since hard butter of a non-tempering type does not have remarkable polymorphism, it is advantageous in that tempering treatment is not required in the production of chocolate. However, hard butter of a non-tempering type is predominantly used as a fat ingredient for chocolate to be used in the above-described combined foods because it is generally recognized to be used with cacao butter only in a limited proportion (JP-A 60-221035).
In the case of per se chocolate sweets such as bar chocolate as well as combined foods with baked confectionery, chocolate is usually eaten at a range of ordinary room temperature, i.e., about 20.degree. C. However, in the case of a combined confectionery such as chocolate coated on ice cream, it is eaten at a temperature range of freezing. When chocolate to be eaten at the former temperature range is eaten at a temperature range of freezing or refrigerating, the mouthfeel thereof becomes hard to bite and eat, and it is difficult to melt in the mouth. In addition, when per se chocolate sweets are produced by using a conventional chocolate material mix for ice coating or the like, the resultant chocolate is unsuitable to per se chocolate sweets because it has very pasty and unpleasant mouthfeel different from conventional per se chocolate sweets such as bar chocolate and tablet chocolate.
JP-A 54-20941 discloses chocolate to be cooled and eaten at a low temperature. By rapid cooling without tempering treatment, while maintaining instable crystals, a product having a low melting point which is suitable for eating at a low temperature can be obtained, though tempering type fats are used. However, there is a limitation that the product thus obtained must be marketed in a frozen state, which is different from the marketing route of conventional per se chocolate sweets. In addition, the above-described patent application also discloses the use of the chocolate for per se chocolate sweets, but mouthfeel thereof is somewhat pasty due to the use of a liquid fat. Then, it is still required to improve physical mouthfeel, when the chocolate is used as per se chocolate sweets.